Yes, you can extend your time. You do get a fair few minutes (but I didn't time it when I played!). Save often. If you feel you're getting close to the time when Gray will return, just go back to the alarm panel outside and hit it again. When you return you should be able to continue the puzzle from where you left off.

I have repaired the capacitors in the tesla coil. I do not have the black light, I have check and recheck the tool chest in Ryans lab. It is not there...What am I missing. And where are the gummy bears??

Please double check the blue tool chest left of Ryan.The black light is there even at start of the game but cannot be taken until it is triggered by Niko's song.The black light is a black fluorescent type bulb.It is in the second drawer protruding from the tool chest.